Pneumatic tool



(No Model.)

J. BOYER. PNBUMATIG TooL. No. 537,629. Patented Apr. 16,1895.

wm vw sll ATENT Price.,

JOSEPHr BOYER, OF ST. LOUIS, MISSOURI.

PN EUMATIC TOOL.

SPECIFICATION forming part of Letters Patent No. 537,629, dated April 16, 1895.-

Application filed November 23, 1894:. Serial N- 529i754- (N0 DlOdGL) i To @ZZ whom it may concern:

Beit known that I, JOSEPH BOYER, a citizen of the United States, residing at the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Pneumatic rFools, of which the following is a description, reference being had to the accompanying drawings, forming part of this speciicat-ion.

My invention relates to that class of toolsl in which compressed air or other pressure and in which the shocks and jars occasioned by the reciprocation of the piston and its action upon the tool shall be reduced to the minimum. Its novelty consists in certain new constructions and arrangements, and combinations and modes of operation, which will oe hereinafter more fully explained and particu-,

larly pointed out in the claims.

My new tool embodies as constituent elements a casing or holder containing a chamber in which the piston is confined and moves;

a tool having its shank or stock fitted in a bore in one end of the casing and projecting into position therein to directly or indi rectly receive a blow from the piston at one end of the stroke of the latter; and an automatic valve mechanism controlling the admission and exhaust of pressure to and from the cylinder or piston-chamber. In these gen-A` eral features my new tool resembles that heretofore patented to me by Letters Patent of the United States No. 277,448, dated May l5,V

1883, and in some respects my present invention consists in improvements upon and modifications of said prior device, while in others it is a departure therefrom and embodies entirely new constructions, arrangements, andi modes of operation.

Like my prior tool my present one has a grasping handle secured to the end of the casing at which the valve mechanism is located and provided with means within the grasp of the operator for controlling the admission of pressure to the tool; while at the opposite end of the casing the tool stock is fitted to reciprocate in the bore of the casing and is adapted to'be held and vdirected in its work by one hand of the operator while with the other he grasps the handle of the tool and admits and cuts off the pressure as necessary. rlhe means for controlling the pressure supply in my present tool diers, however,- from that of my prior one and embodies elements of novelty which constitute certain features of my present invention, as hereinafter set forth; as likewise does the means for securing the handle to thecasing of the tool.

In my prior device the piston, which operates as a hammer or striker for actuating the tool, was moved in both directions in its chamber orcylinder by the action ofthe compressed air, the latter being alternately admitted to and exhausted from the opposite ends of the cylinder. In my present tool the `pressure supply is intermittently7 admittedto and exhausted from `but one end of the piston chamber, to drive the piston forward to deliver its blow, while a constant pressure atrthe other end of the piston-preferably the mechanical pressure of a coiled spring confined within the front end of the piston chamber-is em- I ployed to return the piston to initial position. 'lheautomatic valve mechanism operates to first admit pressure to the rear end of the cylinder, behind the piston, to drive it forward and deliver a blow to the tool, and to then cut off the pressure supply and open the exhaust from said end of the cylinder, to permit the spring to throw the piston back to initial position. lIn my prior tool the automatic Valve was operated by a mechanical connection with the piston. In my present one it is operated by pressure admitted to its opposite sides. I am aware that it is common in this art to operate the valve by such means, but heretofore in tools with which I have been familiar the pressure has been alternately admitted to the opposite sides of the valve and exhausted therefrom. In the Avalve mechanism which I employ the pressure medium is constantly admitted at full press- -ure to one sidel of the valve, acting upon a given area of the valve to constantly press it IOO in one direction, and is intermittently admitted to the opposite side of the valve and permitted to act upon a greater area thereof, to overcome the opposing pressure and move the Valve in the opposite direction, this intermittent admission of pressure to the valve and its exhaust therefrom being controlled by the movement of the piston in the cylinder. In my prior tool the valve chamber and valve were arranged parallel with the cylinder and piston, while in my present one they are arranged transversely across the rear end of the cylinder, between it and the grasping handle of the tool.

Having now described the general character of my new tool I will proceed to explain and set forth my invention in connection with a detailed description of the mechanical embodiment of it shown in the accompanying drawings, in which- Figure 1 is a vertical longitudinal section of the complete tool; Fig. 2, a horizontal section through the handle of the same, upon the line 2-2 of Fig. l; Fig. 3, a sectional detail on the line 3-3 of Fig. 1; Fig. 4, a rear elevation of the block containing the valve chamber and Valve, and Fig. 5 a front elevation of the same; Fig. 6, an enlarged vertical section of the valve chamber and valve, showing the latter in position to admit pressure to the rear end of the cylinder; Fig. 7, acorresponding View with the valve moved to position to cut oif the pressure supply from the cylinder; Fig. 8, a detail vertical section on the line 8-8 of Fig. 3; Fig. 9, a detail view of a portion of the coupling sleeve showing the shape of its teeth which co-operate with the locking key; Fig. 10, a perspective View of said -keyg Fig. 1l, an enlarged sectional detail showing the shape of the threads upon the coupling sleeve and co-operating part; Fig. 12, enlarged perspective details of the devices for se/curing in place the spring co-operating with the throttle lever.

The same numerals of reference are used to indicate identical parts in all the figures.

The casing or holder of the tool, containing the piston chamber and piston, consists of the cylinder 16 having an open rear end and a tapering front end, into a bore in which latter is fitted a bushing 19 within which snugly fits and reciprocates the stock of vthe tool 18. The tool is free to be withdrawn from the holder, and when in use will be held by the hand of the operator at the front end of the casing 16.

Fitted within the cylindrical chamber in the casing 16 is the piston 17 having in this instance a tapered front end, forming a shoulder at the base of the tapered portion, against which shoulder rests the rear end of a coiled spring 21 fitting Within the chamber and surrounding the tapered front end of the piston, and also surrounding at its front end the portion of the bushing 19 which projects into the chamber, and having its bearing against the front end of said chamber. When the piston is given a full forward stroke its tapered front end will contact with the inner end of the tool stock and give the latter a sharp blow,

and when the pressure which has driven thel piston forward is released the spring 2l will throw the piston back to its initial or rearward position. A hole 22 in the casing 16 in front of the piston affords egress and ingress for the air in the front end of the chamber at such movements of the piston.

In assembling the parts the bushing 1 9 is inserted through the piston chamber, from the rear end of the latter, and its reduced front end is driven tightly into the bore 2O in the front end of the casing 16, with its shoulder abutting against the front end of the pistou chamber. The tool stock 18 in this instance is shown as polygonal in cross section, and the opening in the bushing of corresponding shape, to prevent the tool from turning, but this is not essential and the tool stock and bore may be round and the tool be left free to turn. The provision of the bushing 19 furnishes a longer guide-way and support for the Atool stock than could be conveniently done if the latter were simply fitted in thebore in the front end of the casing l16, and enables the `inner end of the tool to be extended into the piston chamber within reach of the piston while aording a support and guide for it within said chamber.

Secured upon the rear end of the casing 16, by means hereinafter described, is a valve block 23, in this instance of the shape in cross section shown in Fig. 3, and having a cylindrical valve chamber 34 extending vertically through it and closed at its upper and lower ends by plugs 35 and 36, Figs. 6 and 7.

Fitted within the valve chamber is a reciprocating piston valve 39 composed of a middle waist portion closed at its upper end by a diaphragm and forming a cylindrical chamber 57 in the middle of the valve, and two opposite tianged portions snugly fitting the sides of the chamber. The rear wall of the chamber is provided with an inlet port 37 communicating with the pressure supply, in this instance with a duct 53 in the handle of the tool, hereinafter described, and with an eX- haust port 40 opening into a duct 4l communieating with the atmosphere. The front wall of the chamberis provided withaport38 opening into the rear end of the cylinder behind the piston. These ports open at their inner ends in circumferential grooves in the Wall of the valve chamber, to equalize the pressure around the Valve, as usual. The port 38 remains open under all positions of the valve 39. When the valve is inthe position shown in Fig. 6 the inlet port 37 is open and the exhaust port 40 closed, so that pressure will be admitted to thecylinder through the ports 37 and 38 and the piston be driven forward to deliver a blow to the tool. When the valve is then moved forward to the position shown in Fig. 7, by the means hereinafter described, the inlet port 37 will be closed and the eX- ICO haust port 40 opened, so that the pressure within the cylinder will escape through the ports 3S and 40 and permit the spring 21 to throw the piston backward to initial position. The novel means for operating the valve 39, to first admit pressure tothe cylinder through the ports 37 and 38 and then exhaust it therefrom through the ports 38 and 40, may be next explained.v The plug 36 which closes the lower end of the valve chamber is provided with a central vertical extension 56 whose cylindrical upper end ts snugly within the waist of the valve, the latter sliding upon this extension 56 as the valve is moved in opposite directions. The extension 56 of the plug 36 is provided with a vertical duct 58 opening at its upper end into the chamber 57 within the waist of the valve and at its lower end into a transverse duct in the plug communicating at its rear end with a port 51 in the rear wall of the valve chamber, which port 514 communicates through a horizontal and vertical duct 52 with the pressure supply, to-wit: with the duct 53 in the handle before referred to. This passage from the chamber 57 within the valve to the pressure supply is always open, so that pressure is constantly admitted to the under side of the diaphragm forming the top of the chamber 57, and tends to hold the valve in and return it to its upper position shown in Fig. 6. T-he pressure tending to hold the Valve in such position isintermittently Overcome and the valve moved to the position shown in Fig. 7 by admitting pressure to the upper side of the valve and permitting it to act upon a larger area of the valve than the diaphragm referred to upon which the pressure beneath the valve acts. To this end the plug 35 which closes the upper end of the valve chamberis provided with a duct 45 opening at its lower end into the space above the valve 39 and communicating at its upper end through the port 44 in the front wall of the valve chamber with a duct 42 extending longitudinally through the wall of the casing 16 and opening at the point 43 into the chamber containing the piston. When the piston is in initial position, at the rear end of the cylinder, itcloses the end 43 of the duct 42, so that no pressure is admitted to the upper side of the valve, but when the piston is thrown forward by the'admission of pressure to the rear end of the cylinder the end of the duct at 43 will be uncovered as the piston reaches the Jforward end of its stroke, and the pressure within the cylinder will be admitted throggh the duct 42, port 44 and duet 45 to the upper side of the valve, and there acting not only upon the upper side of the diaphragm in the waist of the valve but also upon the annular portion of the valve surrounding the diaphragm it overcomes the pressure beneath the valve and forces the latter downward to the position shown in Fig. 7, thereby closing the inlet port 37 and opening the exhaust port 40 and permitting the pressure to escape fromthe cylinder and the plug 35.

spring 21 to throw the piston back to initial position.

For the purpose of preventing the pressure from escaping from the upper side -of the valve, when the exhaust port 40 is opened and the pressure permitted to escape from the cylinder, there is provided a check-valve at some point inthe passage between the upper side of the valve 39 and the cylinder.. In the present instance the check-valve is located at the lower end of the duct 45 in the The valve shown in the drawings consists of a thin circular plate or disk 46 titting loosely over a depending central stem 47 of the plug 35 and yieldingly heldin place, to close the lower end ot the duct 45, by a spring or springs 4S secured to the stem 47 beneath the disk. When the passage 42 communicating with the cylinder is opened by the piston at the end of its forward stroke and the pressurefrom the cylinder admitted through said passage and the duct 45 the disk 46 will readily yield thereto and permit the pressure to pass into the space beneath it and act upon the upper side of the valve 39. When the pressure is exhausted from the cylinder by the opening of the exhaust port 40 the pressure within the valve chamber, beneath the check-valve, will force the disk 46 tightly against its seat and close the lower end of the duct 45 and prevent escape of such pressure.

For the purpose of releasing this pressurewhen the piston has been returned to initial position, and thereby permitting the constant pressure upon the under side of the valve to lift it and again admit pressure to the cylinder to throw the piston forward, the wall of the casing 16 is provided with a second longitudinal duct 49 opening at its front end into the cylinder at a point in front of the piston when the latter is in initial position, and communicating at itsrear end through a port 50 with the space at the upper side of the valve 39 beneath the check-valve. As the spring throws the piston rearward to initial position the front endof the duct 49 will be uncovered and the pressure at the upper side of the valvewill escape through the port 50 and the duct 49 into the cylinder, whereupon the pressure at the under side of the valve will immediately lift the valve and close the port 40 and open the port 37, causing the piston to be thrown forward to deliver another blow and the operation above described to be repeated.

I am aware that reciprocating valves have been operated by constant pressure at one side of them and intermittent pressure at the oppo`- site side, and that the admission and exhaust of such intermittent pressure have been controlled by the piston, but so far as I am aware I am the first in the art to employ a checkvalve of any sort arranged in any manner in IIO the passage controlled by the piston for inter- A duct 59 connects the space at the inner side of the valve, around the central vertical extension 56 of the plug 36, with the exhaust duct 41. This duct 59 is always -open and furnishes ameans of ingress and egress for the air as the valve 39 moves up and down upon the central extension of the plug 36.

The inner ends of the plugs or blocks 36, which form the opposite ends of the valve chamber, are cut away or made of reduced diameter to form annular seats for the flanged ends of the valve, the exhaust ports 50 and 59 opening into these seats. As the valve approaches the end of its stroke in either direction its lianged end cuts off the escape of air in front of it as soon as such Iianged end enters the annular' seat above referred to, so that there is a body of air then confined in front of the valve to cushion it and relieve it of any shock or jar.

From the foregoing description the following operation of the valve mechanism and piston will be understood, starting withthe parts in the position shown in Figs. 1 and 6. When the throttle valve, hereainfter described, controlling the pressure supply in the duct 53, is opened the pressure passes through the ports 37 and 38 into the rear end of the cylinder and drives the piston forward and causes it to deliver a blow to the tool, the coiled spring 2l being compressed by such forward movement of the piston and the air in front of the piston escaping through the opening 22. As the piston reaches the forward limit of its stroke its rear end passes in front of the open end 43 of the duct 42 and uncovers the same, whereupon pressure passes from the cylinder through said duct and the passages 44 and 45 and check-valve 46 into the space above the valve 39 and forces the latter downward, against the pressure upon its under side, to the position shown in Fig. 7, thereby closing the port 37 and opening the exhaust port 40, whereupon the pressure within the cylinder escapes through the ports 38 and 40 and permits the spring to reset the piston. As the latter reaches initial position it uncovers the end of the duct 49 and permits the escape of the pressure in the space above the valve through the exhaust port 50 and passage 49, whereupon the constant pressure upon the under side of the valve lifts the latter again to the position shown in Fig. 6 and again admits pressure to the cylinder. ln this manner the pressure supply, automatically controlled by the valve mechanism, iu co-operation with the spring 21 will cause an exceedingly rapid reciprocation of the piston 17 and consequent actuation of the tool 18.

It will be noticed that when the piston is moved forward to its limit of stroke its rear end will have passed some little distance to the front of the open end 43 of the duct 42, and likewise that when the piston is in its rearward or initial position the front end of its full cylindrical portion is some little distance in rear of the open end of the duct 49. The result of this arrangement is that in its forward movement, to deliver a blow to the tool, the rear end of the piston will clear and uncover the end 43 of the duct 42 before the piston reaches its limit of movement and contacts with the tool, and as the opening of the duct 42 immediately shifts the valve 39 and opens the exhaust from the cylinder it will be seen that the actual impact of the piston with the tool is caused by the momentum of the piston, rather than by the direct action of pressure, and that at the moment of contact the piston is cushioned against the compressed spring 21, the result being that the blow given the tool is an exceedingly sharp, quick and elastic one, instead of a dead blow such as would be produced by the direct action of pressure. The return movement of the piston is begun with the elastic rebound and the tool is relieved of the severe shock and jar incident to many of this class. Furthermore, it will be seen that in the return movement of the piston the duct 49 will be uncovered before the pistou reaches initial position, and inasmuch as the valve is shifted to admit pressure to the rear end of the cylinder the instant the duct 49 is uncovered it will be seen that as the piston reaches in-k itial position it is cushioned against the newly admitted pressure and rebounds therefrom to its next forward stroke. In this manner the shock at each end of the stroke of the pist0n is reduced to the minimum, with a consequent saving of wear and tear upon the tool and injury to the nerves of the operator.

In tools of this class, if the end of the piston is solid and fits snugly against the end of the piston chamber the shock occasioned by suddenly admitting the operating medium at full pressure is much the same as if a powerful blow were given to the piston with some implement. To relieve such shock in my tool I provide the rear end of the piston with a concave recess as indicated by the dotted lines in Fig. 1. The provision of this cavity permits the initial supply of air admitted to the piston chamber to slightly expand and to start the piston forward with an expansive 'elastic pressure instead of with the dead blow of suddenly admitted full pressure. So, too, the provision of the cavity aids to some extent the cushioning of the piston at the end of its backward stroke, causing it to be arrested by the compressible yielding pressure and to be started forward again by the elastic rebound from the same. It will be understood, however, that, the purpose of this provision being merely to relieve the tool from shock, it may be dispensed with without otherwise affecting the operation of the tool.

My novel valve mechanism will operate in the manner described to admit pressure to and exhaust it from the piston chamber behind the piston, no matter by what means theA constant pressure at the front end of the chamber, for resetting the piston, is produced.

IOO

IIO

IZO

As before stated, I prefer to employ a coiled spring confined in the front end of the piston chamber, for that purpose, and the particular construction and arrangement of the parts illustrated in the drawings and heretofore described' are highly advantageous and have proved exceedingly satisfactory, as regards easy and economical construction, efficiency in operation, durability and strength, and general adaptability to the requirements o'f the art; yet such particular construction and arrangement of the parts may be considerably varied without departing from my invention, and so far as the employment of the coiled spring in the front end of the piston chamber is concerned, the resetting spring may be otherwise applied to the piston; or, without departing from the broader scope of my invention other means for producing a constant resetting pressure upon the front end of the piston may be substituted for the spring. may be so shaped that a constantly admitted supply of the compressed air or other operating medium, acting upon a small area of the front end of the piston, will serve the purpose of the spring in resetting the piston after it has delivered its blow to the tool. Such a substitution of the pressure medium for the spring, as a resetting means for the piston, maybe understood without illustration or description here by reference to my aforesaid priorpatent, where it will be seen that the pressure admitted to and exhausted from the front end of the cylinder acts only upon an annular shoulder upon the piston, thus Serving to reset it with much less force than itis driven forward. By admitting a constant supply of the pressure to the front end of the cylinder, instead of intermittently admitting and exhausting it, the piston would be constantly pressed rearward and reset whenever the exhaust from the front end of the cylinder permitted, as will be readily understood.

I am aware that it has heretofore been proposed to move the piston of a pneumatic tool in one direction by pneumatic pressure and in the opposite direction by a coiled spring, and I do not broadly claim the use of a spring in my tool for such purpose, as will be seen from the terms of the respective claims di rected to this feature of myinvention.

The parts so far described, (assuming the part 26 containing the pressure supply duct 53, the exhaust `duct 4l, and the ducts 5l, 52,'

and 59, to be simply a head block or cap piece secured against the rear face of the valve block 23,) would constitute an operative and useful tool and embody all the novel features of myinvention which relate to the automatic valve mechanism and tool proper. Further features of my invention, however, relate to the handle, of which the block 26 above referred to forms anintegral part; to novel means for coupling said handle to the tool proper; and to a novel hand-operated valve mechanism or throttle for admitting and cut- Thus, the piston and its chamber' ting off the pressure supply at will. These features of my invention may be now described.

The handle proper consists preferably of a portion 60 of approximately the shape shown in Figs. l and 2 of the drawings, which is adapted to be grasped in one hand of the operator in the manner of the ordinary hand saw or other like tool, and a reduced reversely curved neck portion connecting the part 60 with the circular block 26. This block is provided in its forward side with a rectangular recess in which fits the middle rearwardly projecting portion of the valve block 23, as seen in Fig. 3, the block 26 thus embracing and snugly fitting said projecting portion ,of the valve block. The rear end of the casing 16 is provided with a peripheral flange 25 over which fits the front end of a coupling sleeve 24 having an internal annular flange engaging the fiange 25. The portion of the sleeve in rear of the casing and ange 25 is internally threaded and screwed upon the threaded circular periphery of the block 26. By means of this connection said block and the handle are securely attached to the tool proper and the valve block held in position between the handle and casing, within the coupling sleeve. To facilitate the assembling of the parts in true position they may be provided with cooperating dowel pins and holes 54 and 55, Figs. 4 and 5.

v The connection of the handle to the tool by the means above described would be reasonably secure for ordinary purposes, but inasmuch as tools of this character are subjected to continuous jarring from the reciprocation of the piston and its action upon the tool, means of connection which in other implements would be amply secure are not always suihcient to prevent the parts becoming loosened from each other. In my present tool I have provided novel means for meeting this difficulty, which means not only prevents the connection of the parts becoming loosened by the jarring of the tool but tends ato cause such jarring to more tightly bind them together. Such means consists of a. springpressed locking key fitted in a longitudinal recess or guide-way and having oblique or cam locking surfaces adapted to engage teeth or notches upon the coupling sleeve and tendingwto force the latter more tightly'upon the part upon which it is screwed. An enlarged IOO perspective view of the locking key is shown in Fig. l0. It tits in a recess or guide-wayin one side of the tool, Fig. 3, the cylindrical rear portion 28 of the guide-way being formed in the block 26 and the reduced rectangular forward portion 3l of the same being formed in the casing 16, an opening at 34Ca through the valve block 23, Figs. 4 and 5, forming the middle connecting portion of the recess or guide-way. As seen in Figs. 3 and 8 the rectangular front end 3l of the guide-way passes beneath the peripheral dange 25 of the casing 16 and its upper side is flush with the surface of said `casing. -The enlarged rear end of the key 27 is cylindrical in shape, while its reduced front end is of rectangular shape in cross section to snugly fit the front end ofthe recess or guide-way and prevent the key from turning. Upon the outer side ofthe rectangular forward half of the key are formed one or more locking ribs or cam surfaces 32, obliquely disposed upon the key and inclined downward from the cylindrical portion ofthe key toward its front end. These locking ribs are adapted to' engage teeth or notches 33 formed upon the inner edge of the internal flange of the coupling sleeve 24, Figs. 8 and 9, such notches or teeth having substantially the same inclination to the line of movement of the key as have the locking ribs 32 of the latter, as seen in Fig. 9. In assembling the parts, the key is held in the rear end of its recess, with the locking ribs in rear of the toothed ange of the sleeve, until the latter is screwed as tightly as possible upon the block 26, in the direction of the arrow in Fig. 8. When the keyis pressed forward its locking ribs 32 engage with the notches 33 in' the flange of the coupling sleeve, as seen in Fig. 8, and a coiled spring 29 confined in the recess behind the key and bearing upon the same tends to drive it farther forward. It will be seen from Figs. 8 and 10 that any forward movement of the key will tend to turn the sleeve 24 in the direction ofthe arrow and screw it more tightly upon the block 26, and in the operation of the tool when any loosenlng of the parts is occasioned by the jarring the spring 29 forces the key forward, causing 1t to take up any play of the sleeve 24 and lock it. tightly upon the block 26. In this manner the spring-pressed key at all times tends to force the sleeve more tightly upon the block and immediately takes up anylooseness occasioned by the jarring and thereby constantly maintains a firm connection of the handle with the valve block and casing.

This locking key and its co-operating de- V1ce may be used to ad vantage Where one part is screwed upon another in any implement or machine subject to shocks or vibrations tending to loosen the connected parts.

For the purpose of additional security in the connection of the handle and valve block with the casing of the tool the threads of the parts 24 and 26, instead of having both faces inclined, in the usual manner, are made of the form shown in Fig. 11, where it will be seen that the retaining surfaces ofthe threads are transverse to the axis of the parts, thus presenting bearing surfaces at right angles to the line of stress and preventing the tendency to a spreading or enlargement of the nut and consequent loosening of the parts, which would otherwise be occasioned by the jarring and stresses to which the tool is subjected.

The novel valve mechanism contained within the grasping portion 6() of the handle may be next described. The duct 53, which communicates with the source of pressure supply, as heretofore referred to, extends upward from the block 26 through the curved neck of the handle and thence downward through the grasping portion and opens through the lower end of the same. Its lower portion within the handle is enlarged to form a cylindrical chamber 6l into Whose lower end is screwed the nipple 62 upon the end of the usual flexible tube leading to the pressure supply. The internally threaded lower end of the chamber 6l is preferably slightly larger in diameter than the body of the chamber, forming an annular shoulder 66 at the lower end of the latter. Snugly fitting within the chamber 6l is a section of rubber or other flexible tubing 63 preferably provided around its lower end with a flange which fits against the shoulder at 66. vA tubular locking plug 64 is screwed into the threaded lower end 0E the chamber, above the nipple 62, and abuts against the shoulder 66 and confines the flange of the tube 63 against said shoulder, while its vertical projecting tubular section extends upward a short distance within the tubing 63. The tubing may, however, be secured within its chamber in any other suitable or convenient manner which will compel the pressure supply to pass through the tube and prevent it passing around it. It will be seen from this construction that the pressure supply may be admitted to the tool or cut off at will by collapsing the tube 63, Fig. 1,and the means which have been illustrated for effecting this may be next described.

Mounted in a cylindrical guide-way?!E opening at its front end into the valve chamber 6l is a sliding plunger 73 having a rounded front end adapted to bear against the rear side of the flexible tube By pressing this plunger forward to the position shown in Figs. 1 and 2 the rearwall of the flexible tube will be pressed tightly against its front wall and the passage through the valve be closed to cutoff the pressure supply. Asa convenient means for operating the plunger 73 there is provided a lever 72 fitting within a narrow recess 68 within the rear half of the handle 60 and hung by its hook 69 upon a fixed pivot pin 70. The body of this lever is inclosed within therecess 68, but its upper end projects therefrom andis provided with a thumbpiece 7l, in position for the thumb of the operator to rest upon it. The lower end of the lever extends through an opening 75 in the sliding plunger 73. A coiled expansive spring 76 confined in a diagonal bore 52 in the handle and bearing against the lever above its fulcrum presses the lower end of the lever forward and yieldingly holds it and the plunger 73 in the position shown in Figs. 1 and 2, with the valve closed. 'When the operator desires to set the tool in motion he has simply to press upon the thumb-piece 7l at the upper end of the lever and rock it slightly upon its fulcrum to permit the plunger 73 to move rearward and the Valve to IOO IIO

open. .This valve is efficient in operation, cheap in construction, and when worn may be easily and quickly replaced with a new one.

' Other means than the lever 72 may be employed for operating the sliding plunger 73, and when a lever such as 72 is used the spring maybe applied to such lever in any suitable manner. The particular arrangement of the spring 76 and its mode of application to the lever in the present instance, however, constitute a novel feature of myinvention, which may now be explained more in detail by reference to Figs. l and 12. The lower end of the spring is fastened to a nipple 77 whose lower end is slotted to form arms 78 which it over and embrace the edge of the lever 72. Secured to the upper end of the spring is a nipple 79 provided in its upper end with a transverse nick 80 adapted to co-operate with a rib 83 upon the lower end of a screw plug 8l which is screwed into the internally threaded upper end of the bore 82and is provided iln its upper end with a nick for the reception of an instrument for turning it. The spring 76 and nipple 79 are held from turning by the engagement of the arms 78 of the lower nipple with the lever 72, andrto permit the screw plug 8l to be turned to regulate the tension of the spring either the niche in the upper end of the nipple 79 has inclined walls or the rib 83 upon the lower end of the plug 81 has beveled sides, so that while the engagement of the one with the other will prevent the plug `from turning and becoming loosened under the jarring of the tool, yet the plug may be positively turned by an in strument engaged with the nick in its upper end, to regulate the tension of the spring.

Means similar to the above may be advantageously employed for holding springs in position in any relation where shocks or jars tend to loosen the spring and the means employed for-holding it in position. Thus the spring 29 which bears against the rear end of the key 27 may be held in place by a nipple and screw plug similar to the nipple 79 and plug Sl above described.

lt is a desideratum in this art to produce a tool of the smallest size and most compact construction, and of the least weight, consistent with the requisite strength and durability, and power and efficiency in operation; and particularly is it desirable to decrease thelength of the tool to the minimum. At the same time it is important that the piston shall have a considerable length of stroke, in order that the pressure may have time to properly act upon it, in order that it may be properly cushioned at each end of its stroke, and in order that it may strike the tool with a sharp elastic momentum blow and rebound without shock. In many tools heretofore devised decreased length of the tool has been attained at sacrifice ofthe length of the stroke of the piston, so that the latter cannot be properly cushioned, has to be started at each construction and arrangement of the parts u which have been shown and described enable me to give the piston full length of stroke,

'with all its attendant advantages, without increasing the length of the tool as awhole. The comparatively short piston, and the arrangement of the spring with one end surrounding the front end of the piston and the other surrounding the inner end of the bushing and tool stock, afford room for the long spring and accommodate the long stroke of the piston without unduly increasing the length of the casing containing the piston chamber; while the arrangement of the valve chamber transversely across the rear end of the piston chamber and its attachment thereto by the head block fitting over and embracing the valve block, and the coupling sleeve surrounding the valve block and screwed upon the head block and binding the parts together, cause the valve mechanism to add but very little to the length of the piston chamber, so that the whole of the tool proper Yis but little longer than the casing containing said chamber.

It will also be seen that the construction employed is adapted to a firm attachment of the several parts together and a maximum resistance to the shocks and stresses to which the tool is subjected. Thus, the casing or holder 16 being cast in a single piece is much better adapted to the latter purpose than is a casing composed of two or more parts screwed together as is common. So, the bushing 19 driven from the interior of the piston chamber through the bore 20 in the end of the casing with its shoulder abutting against the end of the chamber, and with the action of the piston tending to maintain it in position instead of displacing it therefrom, is much ICO more firmly secured to the casing than if it of the parts and the ready removal and re.

placement of any one of them. Thus, if the spring 2l becomes weakened or broken, by simply unscrewing the coupling sleeve 24 the casing 16 may be detached from the valve block and handle, the piston removed, the

old spring replaced with a new one, and the parts be quickly assembled and secured together again. So, if the exible throttle valve While the foregoing and other advantages are derived from the particular construction and arrangement of the parts, yet ,otherl features of my invention are quite independent thereof and in no wise restricted thereto, and I do not wish to be understood, by describing such construction and arrangement in detail and setting forth their advantages, as intending to limit my invention beyond the terms of my respective claims or the requirements of the prior art.

I am aware that it has heretofore been proposed, in very small pneumatic tools for light work, such as dental pluggers, to employ a spring to reset the piston after it has been moved forward by the pressure medium. In heavier tools, such as mine, for boiler calking, and general metal and stone working, it has heretofore been sought to avoid the use of springs, and so far as I am aware no practical and successful tool of this character, employing a spring for resetting the piston, has heretofore been produced. I do not, however, broadly claim the use of a spring for resetting the piston in such a tool, and the novelty of my invention does not consist merely in the employment of such a spring in larger and heavier tools than those in which such springs have heretofore been employed, but in other features clearly set forth in my respective claims.

Having thus fully described my invention, I claiml. In a pneumatic tool, the combination of acasing or holder containing a piston-chamber and adapted to hold a reciprocating tool at its front end, a piston in said chamber adapted to deliver a blow to the tool at the end of its forward stroke, a spring within the chamber for resetting the piston and against the resistance of which the piston is moved by the pressure medium to deliver its blow, and an automatic valve mechanism in xed position at the rear end of the piston-chamber, and operated by constant pressure at one side of the valve and intermittent pressure admitted to the other for controlling the admission of pressure to and its exhaust from the piston-chamber behind the piston, substantially as described.

2. In a pneumatic tool, the combination of a casing or holder containing a piston-chamber, a reciprocating tool fitting in the front end of the casing and projecting into the piston-chamber, a piston in said chamber having a reduced forward end adapted to deliver a blow to the tool at the end of the forward stroke of the piston, a coiled resetting spring confined in the front end of the chamber and surrounding the innerl end of the tool stock at one end and the reduced front end of the piston at the other, and an automatic valve mechanism in fixed position at the rear end of the piston chamber for controlling the admission ot pressure to and its exhaust from the piston chamber behind the piston, substantially as described.

3. In a pneumatic tool, the combination of a casing or holder containing a pistou-chamber opening at its full diameter through the rear end of the casing and through a bore of reduced diameter at the front end of the casing, a shouldered bushing inserted in the casing through its open rear end and fitted tightly in the bore in its front end, a reciprocating tool fitting in said bushing, a piston within the chamber, a coiled spring confined in the front end of the chamber with its front end surrounding the inner end of the bushing and tool and at its rear end bearing against the piston, and an automatic valve mechanism at the rear end of the casing controlling the admission of pressure to and its exhaust from the rear end ofthe piston-chamber behind the piston, substantially as described.

4:. In a pneumatic tool, the combination of a casing or holder containing a piston-chamber and adapted to hold a reciprocating tool at its front end, a piston in said chamber adapted to deliver a blow to the tool at the end of its forward stroke, resetting means for the piston exerting a constant pressure upon the piston and against the resistance of which the piston is driven forward to deliver its blow to the tool, and an automatic valve mechanism in fixed position at the rear end of the pistonchamber operated by the pressure medium to admit pressure to and exhaust it from the rear end of the piston chamber only, substantially as described.

5. In a pneumatic tool, the combination of a casing or holder containing a piston-chamber and adapted to hold a reciprocating tool at its front end, a piston in said chamber adapted to deliver a blow to the tool at the end of its forward stroke, resetting means for the piston exerting a constant pressure upon the piston and against the resistance of which the piston is driven forward to deliver its blow tothe tool, and an automatic valve conned in a fixed chamber at the rear end of the casing and operated by constant pressure at one side of it and intermittent pressure admitted to the other, for controlling the admission of pressure to the piston-chamber behind the piston, substantially as described.

6. In a pneumatic tool, the combination of a casing or holder containing a piston chamber and adapted to hold a reciprocating tool at its front end, a piston in said chamber adapted to deliver a blow to the tool at the end of its forward stroke, resetting means for the piston exerting a constant pressure upon the front end of the piston and against the resistance of which the piston is driven forward to deliver its blow to the tool, a recip- IOO IIO

rocating valve for Controlling the admission of pressure to the piston-chamber behind the "piston, a passage for constantly admitting ber and adapted to hold a reciprocating tool at its front end, a piston in said chamber adapted to deliver a blow to the tool at the end of its forward stroke, resetting means for the piston exerting a constant pressure upon the front end of the piston and against the resistance of which the piston is driven forward to deliverits blow to the tool, a reciprocating valve for controlling the admission of pressure to the piston-chamber behind the piston, a passage for constantly admitting pressure to one side of said valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of said `valve, a check valve in said last mentioned passage, and an exhaust passage controlled by the piston and communicating with the valve chamber between the check-valve and main valve, substantially as described.

8. In a pneumatic tool, the combination of a casing or holder containing a piston-chamber and adapted tohold a reciprocating tool at its front end, a piston-in 'said chamber, adapted to deliver a blow to the tool at the end of its forward stroke, a spring Within the chamber for resetting the piston, and an automatic valve operated by constant pressure at one end of it and intermittent pressure admitted to the other, for controlling the admission of pressure to and its exhaust from the piston-chamber behind the piston, substantially as described.

9. In a pneumatic tool, the combination of a piston-chamber, a piston therein, a resetting spring for the piston, a reciprocating valve for controlling the admission of pressure to and its exhaust from the piston chamber, a passage for constantly admitting pressure to one side of said valve, a second passage controlled by the piston forintermittently admit- 'ting pressure to the opposite side of said valve, and a check valve in said last mentioned passage, substantially as described. "L,

10. In a pneumatic tool, the combination 'of a piston-chamber, a piston therein, a resetting spring for the piston, a reciprocating valve for controlling the admission of pressure to and its exhaust from the piston chamber,a passage for constantly admitting pressure to one side of the valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of said valve, 'and a separate exhaust passage communicating with said last mentioned side of the valve and controlled by the piston, substantially as described.

1l. In a pneumatic tool, the combination of a piston-chamber, apiston therein, a resetting spring for the piston, a reciprocating valve for controlling the admission of pressure to and its exhaust from the piston chamber, a passage for constantly admitting pressure to one side of said valve, a second passage controlled by the'piston for intermittently admitting pressure to the opposite side of the valve, a check valve in said last mentioned passage', and an exhaust passage controlled by the piston and communicating with the valve-chamber between the check valve and main valve, substantially as described.

l2. In a pneumatic tool, the combination of a piston-chamber, a piston therein, resetting means for the piston exerting a constant pressure upon the frontend of the piston and against the resistance of which the piston is driven forward to deliver its blow to the tool, a valve-chamber at the rear end of the pistonchamber, having an inlet and an exhaust port, and a-constantly open port communicating with the piston-chamber behind the piston, and a valve in said valve chamber operating to intermittently admit pressure to and exhaust it from the valve chamber, substantially as described.

13. In apneumatic tool, the combination of a piston-chamber, a piston therein, resetting means for the piston exerting a constant pressure upon the front end of the piston and against the resistance of which the piston is driven forward to deliver its blow to the tool, a valve-chamber at the rear end of the pistonchamber, having an inlet and an exhaust port, and a constantly open port communicating with the piston-chamber behind the piston, a reciprocating valve in the valve-chamber, a passage for constantlyadmitting pressure to one side of the valve, and a second passage controlled by the piston for intermittently admitting pressure to its opposite side7 substantially `as described. Y

-1-1. In a pneumatic tool, the combination of a piston-chamber, a piston therein, resetting means for the piston exerting a constant pressure upon the front end of the piston and against the resistance of which the piston is driven forward to deliver its blow to the tool, a valve-chamber at the rear end of the pistoncbamber, having an inlet and an exhaust port, and a constantly open portcommunicating with the piston-chamber behind the piston, a reciprocating valve in said valve-chamber, a passage for constantly admitting pressure to one side of the valve, a secondpassage controlled by the piston for intermittently admitting pressure tothe opposite side ofthe valve, a check valve in said last mentioned passage, and an exhaust passage communieating with the valve-chamber between the check valve and main valve and controlled by the piston, substantially as described.

l5. In a pneumatic tool, the combination of a piston-chamber, a piston therein, a resetting spring for the piston, a valve-chamber having an inlet and an exhaust port, and communi- IOO IIC

eating with the rear end of the piston chamber by a constantly open port or passage, and a valve in said valve chamber, operating to intermittently admit pressure to and exhaust it from said chamber, substantially as described.

16. In a pneumatic tool, the combination of a piston-chamber, apiston therein, a resetting spring for the piston, a valve-chamber having an inlet and an exhaust port and communieating with the rear end of the piston-chamber by a constantly open port, a reciprocating valve in the valve-chamber, a passage for constantly admitting pressure to one side of the Valve, and a second passage controlled by the piston for intermittently admitting pressure to its opposite side, substantially as described.

17. In a pneumatic tool, the combination of a piston-chamber, a piston therein, a resetting spring for the piston, a valve-chamber having an inlet and au exhaust port and communicating with the rear end of the piston-chamber by a constantly open port, a reciprocating valve in the valve-chamber, a passage for constantly admitting pressure to one side of the valve, for moving it to and yieldingly holding it in position to admit pressure to the chamber, and a second passage controlled by the piston for intermittently admitting pressure to the opposite side of the valve to overcome said constant pressure and move the valve to position to close the inlet port and open the exhaust port, substantially as described.

18. In a pneumatic tool, the combination of a piston-chamber, a piston therein, a resetting spring for the piston, a valve-chamber at the rear end of the piston chamber, having an inlet and an exhaust port and a constantly open port communicating with the piston chamber behind the piston, a reciprocating valve in said chamber, a passage for constantly admitting pressure to one side of the valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of the valve, a check valve in said last mentioned passage, and an exhaust passage communicating with the valve-chamber between the check valve and main valve and controlled by the piston, substantially as described.

19. In an automatic valve mechanism, the combination, with a reciprocating valve, of a' suitably controlled passage for intermittently admitting pressure to one side of said valve, a check valve in said passage, and an exhaust passage communicating with the valve-cham-4 valve;

ber between the check valve and main substantially as described.

20. In au automatic valve mechanism, the combination, with a reciprocating valve, means operating against one side of said valve to constantly press it in one direction, a suitably controlled'passage for intermittently admitting pressure to the opposite side of said valve, and a check valve in said last mentioned passage, substantially as described.

21. In an automatic valve mechanism, the

combination, with a reciprocating valve, of a passage for constantly admitting pressure to one side ot' the valve, a passage suitably controlled for intermittently admitting pressure to the opposite side of said valve, and a check valve in said last mentioned passage, substantially as described.

22. In an automatic valve mechanism, for controlling the admission ot' pressure to and its exhaust from a piston chamber, the com- 'bination, with a reciprocating valve, of a passage for constantly admitting pressure to one side of the Valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of said valve, and a cheek valve in said last mentioned passage, substantially as described.

23. In an automatic valve mechanism, for controlling the admission of pressure to and its exhaust from a piston-chamber, the combination, with a reciprocating valve, of a passage for constantly admitting pressure to one side of the valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of said valve, a check Valve in said last mentioned passage, and an exhaust passage controlled by the piston and communicating with the valve-chainber between the check valve and main valve, substantially as described.

2t. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, resetting means for the piston exerting a constant pressure against its front end and against the resistance of which the piston is driven forward to deliver its blow, a separate valve-block secured to the rear end of the piston chamber to close the same, and containing a valve-chamber having an inlet and an exhaust port, and a constantly open port communicating with the piston-chamber behind the piston, and a reciprocating valvein said valve chamber for intermittently admitting pressure to and exhausting it from the chamber, substantially as described.

25. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, resetting means for the piston exerting a constant pressure against its front end and against the resistance of which the piston is driven forward to deliver its blow, a separate valve block secured to the rear end of the piston-chamber, to close the same, and containing a valve-chamber having an inlet and an exhaust port, and a constantly open port communicating with the piston-chamber behind the piston, a reciprocating valve in said chamber, an inlet passage from the pressure supply for constantly admitting pressure to ICO IIO

IZO

one side of said valve, and a second passage controlled by the piston for intermittently admitting pressure to the opposite side of the valve, substantially as described.

26. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, resetting means for the piston exerting a constant pressure against its front end ure supply for constantly admitting pressure to one side of said valve, a second passage controlled by the piston for intermittently admitting pressure to the opposite side of said Valve, a check valve in said last mentioned passage, and an exhaust passage controlled by the piston and communicating with the valve chamber between the check Valve and main Valve, substantially as described.

27. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, a resetting spring for the piston, aseparate valve-block secured to the rear end of the piston chamber for'closing the same, and containing a valve-chamber transverse to the piston-chamber, said valve-chamber having an inlet and an exhaust port and a constantly open port communicating with the pistonchamber behind the piston, and a reciprocating valve in said valve chamber for intermittently admitting pressure to a'nd exhausting it from the Valve chamber, substantially as described.

28. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, a resetting spring for the piston, a separate Valve block secured to the rear end of the piston-chamber, for closing the same, and containing a valve-chamber' having an inlet and an exhaust port and a constantly open port communicating with the pistou-chamber behind the piston, a reciprocating valve in said chamber, an inlet passage from the pressu re supply for constantly admitting pressure to one side of said valve, and a second passage communicating at one end with the opposite side ofthe valve and extending longitudinally through the wall of the piston-chamber and opening into the latter at a point slightly in rear of the piston when the latter is at the forward limit of its stroke, substantially as described.

29. In a pneumatic tool, the combination of a piston-chamber open at its rear end, a piston therein, a resetting spring for the piston, a separate Valve-block secured to the rear end of the piston chamber, for closing the same, and containing a valve-chamber having an inlet and an exhaust port and a constantly open port communicating with the piston-chamber behind the piston, a passa ge from the pressure `supply for constantly admitting pressure to one side of the valve, a second passage communicating at one end with the opposite side of the valve and extending longitudinally through the wall of the piston-chamber and opening into the latter at a point in rear of the piston when the latter is at the forward limit of its stroke, a check valve in said passage, and an exhaust passage communicating at one end with the valve-chamber between the check valve and main valve and extending longitudinally through the wall of the piston-chamber and opening into the latter a short distance in front of the piston when the latter is in its initial position, substantially as described.

30. In a pneumatic tool, the combination, with the piston-chamber, the valve-block {ity. ting against its rear end and containing the valve-chamber, and the head-block fitting against the rear side-of the valve block, of

the separate coupling sleeve surrounding the valve-block and connecting the piston-charnber and head block, substantially as described.

31. In a pneumatic tool, the combination, with the piston-chamber, the valve-block fitting against its rear end and containing the valve-chamber transverse to the piston-chamber, and the head-block fitting against the rear face of the valve-block and containing the inlet and exhaust passages, of the separate coupling sleeve surrounding the Valveblock and connecting the piston-chamber and head-block, substantially as described.

32. In a pneumatic tool, the combination, with the piston-chamber having a peripheral flange at its rear end, the valve-block iitting against the rear end of said chamber, and the externally threaded head-block tting against the rear `falce of the valve-block, of the coupling sleeve screwed upon the head-block and having at its front end the internal tiange engaging the iiange upon the rear end of the piston-chamber, said sleeve inclosing the valve-block and binding it between the headblock and piston-chamber, substantially as described.

33. In a pneumatic tool, the combination, of the piston-chamber, the valve-block litting against the rear end thereof and containing a valve-chamber transverse to the pistonchamber, said block having an inlet and an exhaust port and a constantly open port communicating with the pistonchamber, the head-block fitting against the rear side of the valve-block and having the pressure supply passage registering with the inlet port of the valve-block and the exhaust passage registering with the exhaust port thereof, the reciprocating valve in the valve-chamber operating to intermittently open and close the inlet and exhaust ports, and t-he coupling sleeve surrounding the valve-block and engaging a flange upon the piston-chamber at its front end and screwed at its rear end upon the head block, substantially as described.

34. In a pneumatic tool, the combination, with the piston-chamber, the head-block, and the coupling sleeve connecting the pistonchamber and head-block, suitably engaging one and screwed upon the other, of the spring- ICO IIO

pressed locking key having a cam surface or rib engaging a notch or projection on the coupling sleeve, substantially as described.

35. In a pneumatic tool, the combination, with the piston-chamber, the valve-block litting against its rear end, the head-block fitting against the rear face of the valve-block, and the couplingsleeve engaging the rear end of the piston-chamber and screwed upon the head-block, of the spring-pressed locking key having the cam surface or rib engaging a notch or projection on the coupling sleeve, substantially as described.

36. In a pneumatic tool, the combination, with the piston-chamber having a peripheral flange at its rear end, the valve-block fitting against the rear end of said chamber, the head-block fitting against the rear face of the valve-block, and the coupling sleeve screwed upon the head block and having atits front end an internal flange engaging the flange upon the piston chamber,of the spring-pressed sliding locking key tting in a guide-way in the piston-chamber and head-block and having the cam surfaces or ribs engaging projections or notches on the coupling sleeve,

substantially as described.

37. In a pneumatic tool or other device, the combination, with two connected members, one screwed to or upon the other, of a springpressed locking key fitted in a guide-way in one member and engaging the other member and exerting a stress upon the latter tending to rturn it and screw the members more tightly together, substantially as described.

38. In a pneumatic tool, the'combination, with two connected members, one screwed to or upon the other, of a spring-pressed sliding key fitted in a guide-way in one member and having a cam surface or rib engaging a notch or projection on the other member and tending to turn the latter and screw the two members more tightly together, substantially as described.

39. In a pneumatic tool or other device, the

combination, with two connected members,

one screwed to or upon the other,andaeoup ling sleeve engaging one and screwed upon the other, for connecting them, of a springpressed locking key confined in a guide-way in one or both members and engaging the coupling sleeve and tending to turn the latter and screw it more tightly upon the threaded member, substantially as described.

40. In a pneumatic tool or other device, the combination, with two connected members, and a coupling sleeve engaging one and screwed upon the other, for connecting them, of a spring-pressed sliding key fitting in a guide-wayin one or both of said members and provided with a cam surface or rib engaging a notch or projection on the coupling sleeve and tending to turn the latter and screw it more tightly upon the threaded member, substantially as described.

41. In a pneumatic tool or other device, the combination of two members, one externally threaded and the other provided with a pei ripheral flange, a coupling sleeve having an internal flange engaging the flanged member and internally threaded to screw upon the other member, and a spring-pressed sliding key fitting in a guide-way and having a cam surface or rib engaging notches or projections on the coupling sleeve and tendingto turn the latter and screw it more tightly upon the threaded member, substantially as described.

42. In a pneumatic tool, the combination, with the tool proper, of a grasping handle secured thereto and having the pressure supply duct extending through it, and a throttle valve in the grasping portion of said handle for controlling said duct, substantially as described.

43. In a pneumatic tool, the combination, with the tool proper, of a handle secu red thereto and composed of a grasping portion and a reduced neck portion connecting it with the tool, the pressure supply duct extending through both portions of the handle, and a throttle Valve in the handle for controlling said duct, substantially as described.

44. In a pneumatic tool, the combination, with the tool proper having a head-block secured to its rear end, of a handle composed of a grasping portion and a connecting neck portion formed integral with said head block, the pressure supply duct extending through both portions of the handle and the head block, and a throttle valve in the handle for controlling said duct, substantially as described.

45. In a pneumatic tool, the combination, with the tool proper having a head block secured to its rear end, said block being provided with an inlet and an exhaust passage, of a handle formed integral with said head block, said handle being composed of a grasping portion substantially in line with the tool proper and a reversely curved neck portion connecting it with the head block, the pressure supply duct extending through the handle and head block, and a throttle valve in the handle for controlling said duet, substantially as described.

46. In a pneumatic tool, the combination, with the tool proper, of a grasping handle secured thereto and having the pressure supply duct extending through it, a throttle Valve in the grasping portion of the handle for controlling said duct, and a pressure piece upon the handle within the grasp of the operator for operating said valve, substantially as described.

47. In a pneumatic tool, the combination, with the tool proper, of a grasping handle secured thereto and having the pressure supply duct extending through it, a throttle valvein the handle for controlling said duct, and a lever confined in a recess in the handle for operating said valve and projecting outside the recess at one end into position to be pressed by the hand ot' the operator, substantially as described.

48. In a pneumatic tool, the combination,

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49. In a pneumatic tool, the combination,l

l with the pressure supply passage,of a valvechamber formed therein, a iiexible tube fitted in said chamber, a tubular locking plug or collar screwed into the valve chamber at one end and entering the flexible tube to hold the latter in position a sliding plunger moving transversely of the chamber and adapted to collapse the tube to close the passage, and a spring-pressed lever engaging said plunger for operating the same and normally holding the plunger in position to close the valve, substantially as described.

50. In a pneumatic tool, the combination, with the pressure supply passage, of a valve chamber formed therein, a iiexible tube fitted in said chamber and provided with a peripheral flange abutting against an annular shoulder, a screw collar for clamping the flange against said shoulder, and means for collapsing the tube in the chamber to close the valve, substantially as described.

5l. In a pneumatic tool, the combination, with the pressure supply passage, of a valvechamber formed therein, a iiexible tube fitted in said chamber and provided at one end with a peripheral flange abutting against an annular shoulder at the end of the chamber,` a tubular collarscrewed into the bore at said end of the chamber and operating to clamp the fiange of the flexible tube againstY said shoulder, and means for collapsing the tube to close the passage through the chamber, substantially as described.

52. In a pneumatic tool, the combination of the piston-chamber, the valve-block fitting against its rear end, the head-block fitting against the rear face of the valve block, the handle formed integral with the head block and composed of the body and neck portions, and the coupling sleeve surrounding the valve-block and connecting the piston-chamber and head -block, substantially as described.

5 3. In a pneumatic tool, the combination of the piston -chamber having the peripheral flange at its rear end, the valve-block fitting lthe piston-chamber having the peripheral `flange at its rear end, the valve-block fitting against the rear end of the pistou chamber, the externally threaded head-block fitting against the rear face of the valve block, the grasping handle formed integral with the head-block and composed of the body and neck portions, the coupling sleeve screwed upon the head block and provided with Vthe internal flange engaging the iiange upon the piston-chamber, and the spring-pressed locking key fitting in a fixed guide-way and having a cam surface or rib engaging the coupling sleeve and tending to turn the same and screw it more tightly upon the head block, substantially as described.

55. In apneumatic tool or other device, the combination, with a coiled spring held atone end from turning, of a nipple attached to its opposite end, and a screw co-operating with said nipple to regulate the tension of the spring, one of said members having a nick or groove and the other' a co-operating rib or projection yieldingly engaging each other, substantially as described.

56. In a pneumatic tool, or other device, the combination, with a coiled spring held from turning at one end, of a nipple secured to the opposite end of the spring, and a screw acting upon said nipple to regulate the teusion of thespring, said screw and nipple having engaging surfaces which yieldingly hold the screw from turning, substantially as de,- scribed. l

57. In a pneumatic tool or other device, the combination, with a coiled spring confined in a bore and held from turning at one end, of a nipple secured to the opposite end of said spring, and a screw plug screwed into the bore and acting upon the nipple to regulate the tension of the spring, said plug and nipple having engaging surfaces which yieldingly holdthe plug from turning, substantially as described.

58. In a pneumatic tool, the combination, with a coiled spring fitting in a bore and held from turning at one end, of a nipple secured tothe opposite end of said spring and provided with a nick or rib, and a screw plug screwed into said bore and provided with a rib or nick to co-operate with the nipple, substantially as and for the purpose described.

59. In a pneumatic tool or other device, the combination, with a spring and a tension-regulating screw therefor, of a member interposed between the spring and screw and held from turning, said member and screw having engaging surfaces which yieldingly hold the screw from turningwhereby loosening of the screw by shocks and jars is prevented.

60. In a pneumatic tool or other device, the combination, with a coiled spring fitting in a bore, and a screw for holding the same in place, of a member fitting in said bore and held from turning, and having a yielding en-v gagement with said screw, whereby loosening of the screw by shocks and jars is prevented.

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61. In a pneumatic tool, the combination of the casing 16 formed of a single piece of metal and containing the piston-chamber open at its rear end and having the reduced bore 2O in its front end, the shouldered bushing 19 driven from the interior of the piston-chamber into the bore 2O with its shoulder abutting against the end of the chamber, the piston 17 having the reduced front end, the coiled spring 21 interposed between the piston and front end of the chamber and surrounding the reduced end ofthe piston at one end and the bushing 19 at its other, and an automatic Valve mechanism controlling the admission of pressure to and its exhaust 4from the rear end of the piston-chamber behind the piston, substantially as described.

62. Ina pneumatic tool, the combination of the casing 16 containing the piston-chamber open at its rear end, the piston 17 in said chamber, the coiled spring 21 confined in the chamberin front ofthe piston, the valve block 23 secured to the rear end of the casing and closing the open rear end ofthe piston chamber, said valve-block having a valve chamber transverse to the piston-chamber and provided with the inlet port 37 and exhaust port 40 and the constantly open port 38 communicating with the piston-chamber behind the piston, the reciprocating valve in said chamber, the passage from the pressure supply for constantly admitting pressure to one side of said valve, and the inlet and exhaust passages controlled by the piston for intermittently admitting pressure to and exhausting it from the opposite side ot' said Valve, substantially as described.

63. In a pneumatic tool, the combination of the casing 16 containing the piston-chamber open at its rear end, the piston 17 in said chamber, the coiled spring 21 confined in the chamber in front of the piston, the valve block 23 secured to the rear end of the casing and closing the open rear end of the piston-chamber, said valve-block having a valve-chamber transverse to the piston-chamber and provided with the inlet port 37 and exhaust port 40 and the constantly open port 38 communicating with the piston-chamber behind the piston, the reciprocating Valve in said chamber, the passage communicating with the pressure supply for constantly admitting. pressure to one side of said valve, the passage communieating with the opposite side of the valve and extending longitudinally through the wall ot` the casing 16 and opening into the pistonchamber ata point in rear of the piston when the latter is in its forward position, the checkvalve in said passage, and the second passage communicating with the valve-chamber between t-he check-valve and main valve and extending forward through the Wall-ofl the casing 16 and opening into the piston-chamber at a point in front of the piston when the latter is in its rearmost position, substantially as described.

64. In an. automatic valve mechanism, the

combination of the valve-chamber 34 having y the inlet port,37 and exhaust port 40 and the constantly open port 38, the reciprocating Valve 39 fitting in said chamber and having the fianged ends and the central chamber 57, the cylindrical projection 56 fitting in the chamber 57 and containing a passage for the constant admission of pressure to the chamber 57, the passage 45 for the intermittent admission of pressure to the upper side of the valve 39, the check-valve 46 at the lower end of said passage, and the exhaust passsage 50 communicating with the valve-chamber between the cheek-valve 46 and the main valve 39, substantially as described.

65. In an automatic valve mechanism, the combination of the valve block 23 containing the cylindrical valve-chamber 34, the plugs 35 and 36 closing the upper and lower ends of said chamber, the ports 37, 38 and 40 in the walls of the Valve-chamber, the reciprocating valve 39 fitting in said chamber and having the flanged ends and the central'chamber 57, the Vertical extension of the block 36 having the cylindrical upper end fitting in the chamber 57, and the passage 58 for the constant admission of pressure to said chamber, the passage 45 in the plug 35, controlled by the piston vin the piston chamber, for the intermittent admission of pressure to the upper side of the valve 39, the spring-pressed checkvalve 46 carried by the pendent stem 47 of the plug 35 and co-operating with the lower end ot' the passage 45, and the exhaust passage 50 controlled by the piston and communicating with the space between the checkvalve 46 and the upper side of the valve 39, substantially as described.

66. In a pneumatic tool, the combination of the casing 16 containing the piston-chamber open at its rear end, the valve-block 23 fitting against the rear end of said casing, said block consisting of a front plate and a rearwardly projecting rectangular portion containing the Valve chamber, the head block 26 fitting against the rear side of the valve block and provided with the recess embracing the rearward projection of the Valve-block, and the coupling sleeve 24 screwed upon the headblock 26 and having the internal flange at its frontend engaging the peripheral flange 25 upon the rear end of the casing 16, substantially as described.

67. In a pneumatic tool, the combination of the casing 16 containing the piston-chamber open at its rear end, the valve-block 23 fitting against the rear end of said casing, the headblock 26 fitting against the rear face of the valve-block, the coupling sleeve 24 screwed upon the head-block'and having the internal flange engaging the peripheral flange 25 upon the rear end of the casing 16, the locking key 27 fitted in a guide-way formed in the block 26 and wall of the casing 16 and passing through the Valve-block 23, said key having the cam surfaces 32 co-operating with the notches 33 upon the flange of the coupling sleeve, and the spring 29 bearing against the key 27, substantially as described.

68. In a pneumatic tool, the combination, with the tool proper having the head-block 26 secured to its rear en'd, of the handle formed integral with said head-block and composed of the grasping portion 60 and the curved neck portion connecting it with said block, the pressurey supply passage 53 extending through the grasping portion and neck ot the handle and through the head-block, the valvechamber 6l formed in said passage, the fiexible tube 63 confined in said chamber, the sliding plunger 73 movable transversely of the valve-chamber to close the valve, and means within the grasp ofthe operator for operating said plunger, substantially as described.

69. In a pneumatic tool, the combination, with the tool proper, of the handle having the grasping portion 60 and containing the pressure supply passage 53, the valve-chamber 61 formed in said passage, the flexible tribe 63 fitting in said chamber, the sliding plunger 73 for collapsing said tube across said chamber, the lever 72 pivoted in the recess 68 in the handle and engaging the plunger 73 at its lower end and projecting outside said recess at its upper end, and the spring 76 acting upon said lever, substantially as described.

70. In a pneumatic tool, the combination, with the tool proper, of the handle having a grasping portion 60 and containing the pressure supply passage 53, the valve-chamber 61 formed in said passage, the flexible tube 63 confined in said chamber, the sliding plunger 73 co-operating with said tube, the lever 72 pivoted in the recess 68 in the handle and engaging the plunger 73 at its lower end and projecting outside said recess at its upper end, the coiled spring 76 confined in the bore 82 and secured at its lower end to the nipple 77 embracing the edge of the lever 72, the nipple 79 secured to the upper end of said spring and having the nick 8O in its upper end,` and the screw plug 8l screwed into the upper end of the bore 82 and having the rib 83 engaging the nick 80 of the nipple 79, substantially as described.

7l. In a pneumaticltool, the combination, with the tool proper, of the handle having the grasping portion 60 and containing the pressure supply passage 53, the valve-chamber 61 formed in said passage, the flexible tube 63 fitted in said chamber and having the peripheral flange at its lower end fitting against the shoulder 66, the screw collar 64 screwed into the threaded bore beneath the valve chamber, for clamping said flange against the shoulder 66, the nipple 62 of the supply pipe screwed into the lower end of said bore beneath the collar 64, and means within the grasp of the operator for collapsing the tube 63 to close the passage, substantially as described.

72. In a pneumatic tool, the combination Jwith the tool proper, of the handle having,

the grasping portion 60 and containing the pressure supply passage 53, the valve-chamber 61 formed in said passage, the fiexible tube 63 fitted in said chamber and having the peripheral flange at its lower end fitting against the shoulder 66, the screw collar 64 screwed into thethreaded bore beneath the valve chamber, for clamping said tiange against the shoulder 66, the nipple 62 of the supply pipe screwed into the lower end of said bore beneath the collar 64, the sliding plunger 73 movable transversely of the valve chamber to close the valve, and the lever 72 fitted in the recess 68 in thel handle and cooperating with the plunger 73, substantially as described.

73. In a pneumatic tool, the combination, with the tool proper,of the handle having the grasping portion 60 containing the pressure supply passage 53, the valve chamber 6l formed in said passage, the iiexible tube 63 fitting in said chamber, and having the peripheral ange at its lower end, the screw collar 64 screwed into the threaded bore beneath the valve-chamber and clamping the flange ot' the tube 63 against the shoulder 66, the nipple 62 of the supply pipe screwed into said bore beneath the collar 64, the sliding plunger 73 co-operating with the tube 63 and having the slot 75, the lever 72 inclosed in the recess 68 in the handle and having the hook 69 by which it is hung upon the fixed fulcrum pin 70, said lever projecting at its upper end outside the recess 68 and having the thumb-piece 7l, and the spring 76 acting on said lever to normally hold the plunger 73 in position to close the valve, substantially as described.

74. In an automatic valve mechanism, the combination of the valve-chamber, the reciprocating valve 39 having the cylindrical middle or waist portion containing the chamber 57 and the cylindrical iianged end portions, and the part 56, fitting in the chamber 57, and containing the duct 58, substantially as and for the purpose described.

75. In an automatic valve mechanism, the combination, with the valve chamber 23, having the inlet port 37 and exhaust port 40 and the constantly open port 38, of the reciprocating valve 39 having the middle waist portion, closed by a suitable diaphragm, and the cylindrical fianged end portions, said valve operating when moved in one direction to open the port 37 and close the port 4Q, and when moved in the other direction to close the port 37 and open the port 40, substantially as described.

76. In an automatic valve mechanism, the combination, with the valve chamber 23, having the inlet port'37 and exhaust port 40 and the constantly open port 38, of the reciprocating valve 39 having the middle waist portion, closed by a suitable diaphragm, and the cylindrical fianged end portions, said valve being moved in one direction by constant pressure and in the opposite direction by intermittently admitted pressure, and operating ICO IIO

when moved in one direction to open the port having the annular seats formed in them for 37 and close the port 40, and when moved in the flanged ends of the valve, l.nd the tubuthe opposite direction to close the port 37 and lar extension 56 of the block 36 fitting; in the open the port 40, substantially as described. chamber 57 and containing the duct 58, sub- 5 77. In an automatic valve mechanism, Iche stantially as described.

combination of the valve chamber, the recip- TOSEPH BOYER rocating valve 39 having the cylindrical Waist portion containing the chamber 57, and the Witnesses: cylindrical flanged end portions, theblcks 35 ALFRED J. DOUGHTY, xo 36 forming the ends of the Valve chamber and EMIL VVENGER. 

